1. Field of the Invention
This invention relates to apparatus for recording audio and video signals and, more particularly, to novel and highly-effective apparatus including a rotary magnetic head device for recording a frequency-modulated audio signal, together with a video signal, in successive oblique tracks on a magnetic tape.
2. Description of the Prior Art
A compact video tape recorder has been proposed for use with a magnetic tape having a width of eight millimeters. In such a compact video tape recorder, when recording a color television signal on the magnetic tape, a frequency-modulated audio signal is mixed with a processed color video signal. The frequency-modulated audio signal is produced by frequency-modulating a carrier with an audio signal. The processed color video signal is composed of a frequency-modulated luminance signal and a chrominance signal. The frequency-modulated luminance signal is produced by frequency-modulating an appropriate carrier with a luminance signal separated from the color television signal. The chrominance signal is also separated from the color television signal and is frequency-converted to a frequency band lower than the frequency band of the frequency-modulated luminance signal. The frequency-modulated audio signal is recorded, together with the processed color video signal, in oblique tracks on the magnetic tape by means including a rotary magnetic head.
In recording the frequency-modulated audio signal and the processed color video signal, two operational modes are selectively adopted in a compact video tape recorder. In one of these operational modes, which will be referred to as an SP recording mode, the speed at which the magnetic tape is transported is relatively high so that oblique tracks are formed on the magnetic tape with spaces or so-called guard bands between successive tracks. In the other of the operational modes, which will be referred to as an LP recording mode, the speed at which the magnetic tape is transported is reduced so that successive oblique tracks are positioned on the magnetic tape immediately adjacent to one another. In other words, in the second operational mode, the successive tracks are contiguous and the guard bands between adjacent tracks are eliminated.
In reproducing the recorded signal, cross talk is a problem where the signal has been recorded in the second operational mode described above. In particular, the problem of cross talk arises in respect of the frequency-modulated audio signal read from the magnetic tape in the reproduction mode. Cross talk is a problem with respect to the audio signal because of the relatively low frequency band of the frequency-modulated audio signal read from the magnetic tape and because of the overlap by the heads of at least one track adjacent to the track being scanned when reproducing signals that have been recorded in the LP recording mode.
In order to eliminate or minimize cross talk in the frequency-modulated audio signal reproduced from a magnetic tape on which the signal has been recorded in the LP recording mode, it has been proposed to record the frequency-modulated audio signal on the magnetic tape with respectively different carrier frequencies in successive oblique tracks. In a video tape recorder which is used with a magnetic tape having a width of a half inch, this enables reproduction of audio signals of improved quality. However, in such case, the frequency band of the frequency-modulated audio signal is expanded with the result that the frequency band of the processed video signal is to a degree suppressed (contracted). Further, the video tape recorder employing this technique has the disadvantage that the circuitry is complicated and the cost is increased. Consequently, such measures are not suitable for a compact video tape recorder used with a magnetic tape having a width of 8 millimeters.